我需要一些帮助来尝试从父表中删除一行但不删除子表。我有这张表 MyEntityA。这有 2 个表 MyEntityB 的外键,例如:
@PersistenceCapable(detachable = "true")
public class MyEntityA implements Serializable {
private static final long serialVersionUID = 3575973891490133579L;
/*
* KEYS
*/
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.UUIDHEX)
@Column(name = “Id", jdbcType = "VARCHAR", length = 32)
private String Id;
@Persistent(defaultFetchGroup = "true", dependent = "true")
@Column(name = "CURRENTCLIENT", jdbcType = "VARCHAR", length = 32)
@ForeignKey(name = “MY_ENTITY_B_FK1", deleteAction = ForeignKeyAction.RESTRICT, table = “MY_ENTITY_B", columns = {
@Column(name = “ID") }, updateAction = ForeignKeyAction.RESTRICT)
private MyEntityB currentClient;
@Persistent(defaultFetchGroup = "true", dependent = "true")
@Column(name = "RELATEDTO", jdbcType = "VARCHAR", length = 32)
@ForeignKey(name = “MY_ENTYTY_B_FK2", deleteAction = ForeignKeyAction.RESTRICT, table = "MY_ENTITY_B", columns = {
@Column(name = “ID") }, updateAction = ForeignKeyAction.RESTRICT)
private MyEntityB relatedTo;
public Relationship() {
}
public MyEntityB getCurrentClient() {
return currentClient;
}
public void setCurrentClient(MyEntityB currentClient) {
this.currentClient = currentClient;
}
public MyEntityB getRelatedTo() {
return relatedTo;
}
public void setRelatedTo(MyEntityB relatedTo) {
this.relatedTo = relatedTo;
}
}
现在,使用 JDO,当我试图从表 MyEntityA 中删除一行时,如下所示:
PersistenceManager pm = …
MyEntityA objectById = pm.getObjectById(MyEntityA.class,”abc”);
pm.deletePersistent(objectById)
或者像:
PersistenceManager pm = …
MyEntityA objectById = pm.getObjectById(MyEntityA.class,”abc”);
objectById.setRelatedTo(null);
objectById.setCurrentClient(null);
pm.makePersistent(objectById);
pm.deletePersistent(objectById)
在这两种情况下,代码都将删除表 MyEntityA 中的行和表 MyEntityB 中的行,这些行在表 MyEntityA 中被引用。我希望我可以从 MyEntityA 中删除该行,但不要触摸 MyEntityB 表中的行。
有人可以帮助我吗?